Neutron Definition and 771 Threads

"neutron collides elastically with a helium nucleus" Homework Statement A neutron collides elastically with a helium nucleus (at rest initially) whose mass is four times that of the neutron. The helium nucleus is observed to rebound at an angle θ'2 = 40° from the neutron's initial...

Edit: nvm

Hi all. I am going to be doing an experiment involving neutron scatter. I am going to be firing fast neutrons into water and then detecting the thermal neutrons scattered. I am also going to look into thermal neutron capture where the hydrogen atom captures the thermal neutron and gives off a...

Despite sharing similar physical properties(neutron and proton having little variation in masses, protons and neutron being made up of quarks, both elementary particles are held together by the strong force) why is the decay time for like a neutron 10 minutes and the decay time for like a...

Hi, I did some calculations and I worked out the density of 1 neutron to be about 3.19887549*10^57 kg/m^3. However, I want to know if the method I used is correct. Density = mass/volume, correct? If this is true, then Density = [mass of neutron]/[volume of neutron] I found the volume of a...

Hi What is the best book about neutron scattering and diffusion? Regards

Here's a question. Why does slow neutron is most likely to cause a nuclear fission in Uranium 235, compare to a fast neutron?

I have two nuclear engineer related questions, please bear with me. 1. Why is hydraulic material (like water) is good to shield against neutrons? Why not high Z material like lead? 2. In cross section vs. energy of the nuclei, the curve of the graph undergoes 1/E relationship until it hits...

Can someone explain what "hardening" of a neutron spectra means?

Straight forward question. What would prevent the process of a giant lump of neutrons from forming a stable nucleus?

a) I need a simple description of how a Neutron Generator is built and how it works. b) Where can I see a picture of what a Neutron Generator looks like? c) What is a Plasma Focus (PF) Neutron Generator? d) Is PF the only type of Neutron Generator or are there other types?

when two neutron stars collide, do they creat both a balck hole and release gamma rays or does it happen in stages?

Homework Statement Assuming a neutron star is made from an incompressible material, what is the hydraulic pressure 50m below the surface? Mass = 1.98x10^30kg Radius = 10km 2. The attempt at a solution g=GM/r^2 = (6.67x10^-11 x 1.98x10^30)/ 10000^2 = 1.32x10^12 m/s^2 P=P_{0} + \rhogh Pa...

Homework Statement A neutron with kinetic energy T= 2mc^2 (m=rest mass),strikes another stationary neutron.What will be the combined kinetic energy of both the neutrons in the frame of their centre of inertia and the momentum p of each neutron in that frame.what is the velocity of the...

The binding energy for nucleon in a light atom (like deuterium) is lower than the binding energy for nucleon in a heavier, more stable element like iron. Suppose you remove the neutron from the light atom, and allow it to conjoin (by neutron capture) with an element that had an atomic number...

I have a problem here that has me a bit suck: In scattering between incident neutrons and target protons at rest, show that the angle between the two scattered particles is always 90 degrees. I have set up the conservation of energy and momentum equations and have: Energy: Tn=T'n+Tp...

Hi, here's the problem: "a neutron at rest decays into a proton with a decay energy of 0.78MeV. What is the maximum kinetic energy of the proton left behind?" here's what I've tried: In this decay, I assumed that although it's not mentioned, there would be something negatively charged...

Homework Statement If you were given 4 cookies, each emitter different ray 1)Alpha, 2)Beta,3) Gamma , 4)neutron You have to make decision of the following: a)eat one of the cookies b)dispose one of the cookies at storage facility called WHIP c)put one of the cookies in your pocket...

Homework Statement A neutron collides elastically with a helium nucleus (at rest initially) whose mass is four times that of the neutron. The helium nucleus is observed to rebound at an angle θ'2 = 41° from the neutron's initial direction. The neutron's initial speed is 6.2 x10^5 m/s...

Most accepted theories make sense, but the energies involved in the beta decay of a neutron into a proton confuses me. How can a down quark change into an up quark by emiting an electron and an anti electron neutrino via a w boson, the figures don't add up! Using the figures of mass it goes...

Homework Statement The Gravitational binding energy of an object consisting of loose material, held together by gravity alone, is the amount of energy required to pull all of the material apart, to infinity. the gravitational binding energy Ug is roughly given by GM^2/R. how fast do you have...

Homework Statement Certain neutron stars (extremely dense stars) are believed to be rotating at about 6 rev/s. If such a star has a radius of 15 km, what must be its minimum mass so that material on its surface remains in place during the rapid rotation? G=6.67*10-11m3 kg-1 s-2 Homework...

why does fission chamber start to work from neutron fluxes more than source range in spite of being a kind of ionization chamber that is sensitive to gamma rays?

I've never really understood how a bound neutron can have a kinetic energy and potential energy associated with it. Further, I'm not sure that I quite understand what the potential energy of a free neutron means. I know that these questions might be rather elementary, but when I stopped to think...

Just over half-way down this page:- http://www.embedded.com/columns/technicalinsights/220301380?cid=RSSfeed_embedded_news it says:- "These sunspot counts show variation on a cycle of roughly 11 years. By overlaying Oulu neutron measurements with sunspot count data since 1964, we see that...

Say we slowly add mass to a neutron star till it collapses to a black hole. Just before it does has time in the neutron star almost come to a stop? Is the passage of time different for different locations in the neutron star just before it collapses? Would the strings of string theory come to a...

Gravity acceleration value depend on planet and stars mass. On the earth, the well known average value is 9.81 ms-2. On the sun, I read 1200 ms-2; is it true ? does exist a curve giving values depending on mass ?

Do Neutrons and anti-Neutrons annihilate? I can't imagine any reason why they would, I just thought I'd check.

Hi! I hope I've posted this in the right section, but it definitely deals with the nucleus, so here goes. I'm doing a presentation on Boron Neutron Capture Therapy, which, if you don't know, puts boron inside tumor cells, shines a neutron beam onto those cells, which causes the boron inside...

If a neutron star accumulate materials from its companion star ,then it's mass exceeded Tolman–Oppenheimer–Volkoff limit, it will collapse into a black hole! My question is ,in this case ,it will produce "gamma-ray burst"?

Homework Statement A neutron has an elastic collision with a stationary deuteron. Mass of neutron is 1 amu, mass of deuteron is 2 amu. the neutron is deflected through 90 degree angle. Prove that the neutron loses 2/3 of it's initial kinetic energy to the deuteron. Homework Equations...

How many neutrino emission mechanism, that causes the cooling of star, are there in neutron star? And How, what equation, to calculate the emissivity of each mechanism? thankfully, First

Hi, in a lecture I was told that the cooling of neutron stars cannot happen via the 'direct' Urca process (beta decay and inverse beta decay), because the created particles cannot go into occupied states (Pauli exclusion). The 'modified' Urca process was introduced, with an additional neutron...

I was wondering about the light emitted by one of these neutron stars. To my limited knowledge, neutron stars are among the discrete objects in the observable universe with the strongest gravitational and EM fields [black holes beat the living crap out of neutron stars, but that's besides the...

I am looking for thermal neutron scattering cross sections (0.025eV) for individual isotopes, having found non isotopic data for most elements in a textbook. The most comprehensive cross section database appears to be http://www.nndc.bnl.gov/sigma/index.jsp?as=238&lib=endfb7.0&nsub=10"...

Homework Statement Calculate the binding energy of a neutron in 14N Homework Equations E=mc^2 delta m * 1u + E The Attempt at a Solution The mass of Nitrogen (from periodic table): 14.007amu Calculated mass of N: 7 protons (7 * 1.007277amu) + 7 neutrons (7* 1.008665amu) +...

Homework Statement \ (From a past exam paper) Na-24 can be produced by irradiation of 27-Al with energetic neutrons. It decays by beta emission. An aluminium sample of mass m=0.2g was irradiated by energetic neutrons for a period of 1 hour. Two hours after the end of irradiation the total...

I was reading a blog where someone stated that the decay of a free neutron is characterized by a 'mean lifetime' but not by a half-life. They went on to indicate that the decay time is not random (in the sense that leads to a true half life) but rather most decay at the mean lifetime (said to...

Neutron Stars and Special Relativity and General Relativity Here is a question which I can't quite wrap my head around: Suppose we have a Neutron Star that is borderline on the Chandrasekhar limit in its rest frame. In another frame, the Neutron star is moving. As a result, its density...

Hey all, My year 13 physics students stumped me with this one: Why don't Neutron-Neutron (or P-P for that matter) states exist? Thanks in anticipation... Mr T

if you took plain neutrons, and put them in a bottle would a bottle full of neutrons weigh less than a bottle of bear protons with no electrons arround?

hi folks, last problem I can't get done here. I usually have a good idea of where to start, what to use. but I'm a bit flummoxed. Homework Statement A neutron, of mass m = 1.67 10-27 kg, is localized inside a carbon nucleus, of radius 7.0 fm (1 fm 10-15 m). Use the uncertainty relations...

1. Homework Statement [/b] A high energy beam of neutrons of intensity 10^6 s^-1 transverses a target of 238 U of thin foil whose density per unit area is 10^-1 kg m^-2. If the elastic and in elastic cross-sections are 1.4 and 2.0 b, respectively, calculate(a) the attenuation of the beam(b) the...

Homework Statement A high energy beam of neutrons of intensity 10^6 s^-1 transverses a target of 238 U of thin foil whose density per unit area is 10^-1 kg m^-2. If the elastic and in elastic cross-sections are 1.4 and 2.0 b, respectively, calculate(a) the attenuation of the beam(b) the rate of...

hi again folks. this week's set of problems is getting my goat. here's another I can't seem to figure out. Homework Statement In a neutron two-slit diffraction experiment, the slits are 65 µm apart. If the third diffraction maximum is detected at an angle of 2 multiplied by 10-7 rad, what...

I meant to title it "Neutrons packed together" Since neutrons can be packed together in a neutron star, would it be possible to take say five neutrons and pack them together and make a neutroium nucleus. And if not, how come?

If a person could orbit close to a neutron star what color would it appear to be? I have always imgained them to be blue, but this might be totally wrong. :rolleyes:

Since neutrons have no electric charge, how is it that a neutron star is able to produce a magnetic field? :confused:

Hi everybody When fast neutrons hit isolated protons (eg. hydrogen cores in paraffin) the neutrons kinetic energy is transferred to the proton (as they have aproximatly the same mass), which is detectable by a geiger counter, while the neutron is stoped. Thats how far I got after several...

Homework Statement Neutron stars, such as the one at the center of the Crab Nebula, have about the same mass as our sun but a much smaller diameter. If you weigh 650 N on the earth, what would be your weight on the surface of a neutron star that has the same mass as our sun and a diameter...